Temperature dependent formation of ZnO and Zn2SiO4 nanoparticles by ion implantation and thermal annealing

ZnO and Zn2SiO4 nanoparticles have been synthesized by dual beam implantation of 45 keV ZnO− molecular ions and 15 keV O− ions into Si (100) substrates at room temperature to fluences of 1 × 1017 and 2 × 1017 ions/cm2, respectively. Implanted samples were annealed at different temperatures in a mixture of Ar and H2 for 1 h. Rutherford backscattering spectrometry (RBS) was used to confirm the implanted ion fluences. The diffusion of Zn and O ions due to annealing was studied by using X-ray photoelectron spectroscopy (XPS). It was observed that at 700 °C annealing temperature, oxygen diffused into the substrate whereas Zn diffused in both directions; at 900 °C, oxygen diffused more into the substrate but the Zn diffused outward toward the surface. X-ray diffraction (XRD) was used to investigate the phase formation and particle sizes. At 700 °C annealing temperature, ZnO phase with an average nanoparticle size of ∼17.5 nm was observed whereas at 900 °C annealing temperature, Zn2SiO4 phase with an average nanoparticle size of ∼19 nm was observed.